In many applications, gas turbine engines are known to utilize reverse flow combustors for generating hot gases therein. In such combustors, the gases of combustion must reverse their direction of flow approximately 180 degrees before being applied to the turbine wheel. As a result, the "g" forces are generally perpendicular to the direction of flow within the combustor of the gas turbine engine.
By reason of the direction of the "g" forces, there is an undesirable interference with the aerodynamics of the air/fuel mixture. It would, thus, be desirable to avoid such aerodynamic interference by in some way avoiding an arrangement wherein the "g" forces are perpendicular to the direction of flow through the combustor. Still more specifically, it would be highly desirable to provide a combustor wherein the "g" forces are in the same direction as flow through the combustor.
However, while so doing, it must be kept in mind that the combustor must have a sufficient volume to achieve a satisfactory performance level. At the same time, there should not be any increase in engine envelope or overall weight. Still further, a reduction in the number of fuel injectors and the overall weight of the engine would be desirable to reduce cost.
In addition to the foregoing problems and considerations, there is another problem of considerable significance that requires attention in gas turbine engine combustor design. In combustors, a carbonaceous fuel is typically combusted with air to produce the hot gases of combustion but one difficulty in the operation and use of a combustor is carbon buildup which results when the fuel is not completely oxidized and elemental carbon is formed within the combustion chamber. If the combustor walls are not free of carbon buildup, carbon can break away and cause damage to downstream components as well as impair the efficiency of the combustor and gas turbine engine.
More specifically, gas turbine engine combustors are typically used to produce hot gases for driving turbine wheels. As carbon builds up, particles thereof typically break free and then flow with the hot gases of combustion through the turbine wheel where particulate carbon may erode the turbine nozzle and turbine wheel. Furthermore, carbon deposits can build up on the surface of the turbine nozzle and restrict flow to causes performance losses.
Still another problem associated with excessive carbon production is the existence of a massive black exhaust plume which is highly undesirable.
Presently, it is believed that a substantial portion of the carbon produced is a result of liquid phase pyrolysis during liquid fuel droplet evaporation. Some gas phase carbon probably also results from the cracking reactions. However, gas phase carbon is on the molecular level and much less harmful than liquid phase carbon which is on the order of microns for purposes of comparison.
Since it is believed that the carbon is a result of liquid phase pyrolysis, it is essential to achieve rapid fuel evaporation. This is believed to be the best known manner of minimizing liquid phase carbon. However, combustors have not been entirely satisfactory in addressing these serious carbon problems.
The present invention is directed to overcoming one or more of the foregoing problems and achieving one or more of the resulting objects.